1. Field of the Invention
This invention pertains generally to computer accessory support structures, and more particularly, to a chair-mounted apparatus for the ergonomically optimum placement of a computer pointing device.
2. Description of the Background Art
With the use of computers becoming almost universal, cumulative trauma disorders that result therefrom have proliferated. This disorder is responsible for a significant amount of lost work time and high labor turnover. The most commonly known cumulative trauma disorder is Carpal Tunnel Syndrome (CTS). CTS occurs when there is an impingement of the median nerve that is located within the wrist caused by excessive stress on joints and tendons. It typically manifests itself with symptoms such as pain, numbness and/or stiffness in the hands, wrist, arm, shoulder and neck. CTS has also been known to cause a loss of range of motion in the shoulder as well as loss of grip strength of the hand. Typically, treatments for CTS may range from noninvasive techniques such as physical therapy that includes joint manipulation, ultrasound, icing and electro-muscle stimulation, to ingestion of anti-inflammatory drugs, and to invasive procedures such as surgery for removing scar tissue within the wrist that impinges the median nerve.
The use of computers have been attributed as the primary cause of CTS. Using computers physically involve repetitive tasks, such as gripping, pushing and reaching for items such as the keyboard and pointing device. This is because the position of the user relative to the keyboard often requires the extension of upper extremities, such as the neck and shoulder, as well as the arms and hands from the seating apparatus to the keyboard. This lack of optimum positioning, coupled with the highly repetitive nature required for keyboard use, results in the aforementioned cumulative trauma injury. The high repetition nature of computer use, along with forceful and awkward postures, exposes the computer user to CTS. To alleviate or eliminate such injuries due to keyboard usage, keyboard drawers or platforms have been developed. The primary object of these devices is to provide an optimum positioning between the user and keyboard, such that the user's upper extremities, arms and hands do not have to extend unnaturally for the prolonged periods of time normally associated with computer usage.
Such known keyboard drawers or platforms, however, are not always effective in preventing cumulative trauma injuries that result from using computer pointing devices, such as a mouse, trackball or touchpad. Use of these computer pointing devices entail repetitive motion of one side of the body extending down from the neck, shoulder, arm, wrist and hand. Keyboard drawers or platforms are typically maintained in a fixed position relative to the computer monitor as opposed to a fixed position relative to the user. Since use of computer pointing devices only involves one hand at a time, having to adjust and position oneself relative to the keyboard drawer or platform is cumbersome and inconvenient. Even if one is able to initially situated herself in a position that optimizes use of the computer pointing device, and viewing of the monitor, having to maintain that position over an extended time will be uncomfortable, thereby, necessitating body movement away from the optimum position. Additionally, the recent rise in popularity of internet usage for activities such as "web surfing", which predominantly requires use of a mouse, has resulted in an increased incidence of cumulative trauma injuries. Chiropractic doctors, who often are called upon to treat cumulative trauma injuries like CTS, have reported that the repetitive motion required for manipulating a mouse, coupled with mouse being placed on a horizontal surface adjacent the keyboard, has accentuated CTS. This fixed positional relationship of the mouse requires unnatural movement of the wrist and arms which result in the aforementioned injuries.
Since excessive stress on joints and tendons is a principle cause of CTS, repetitive motions should be maintained well within the range of motion of that joint. Such activities should ideally be performed with the joints at approximately the midpoint of their range of movement. When force is being applied by the hand, the wrist should be kept straight and the elbow bent at a right angle. All side-to-side deviations of the wrist should be avoided, and the hands should be kept in line with the forearms.
There are devices which have been developed to provide support for a computer pointing device, which help solve the problem of having to maintain the keyboard drawer or platform in a fixed relation to the computer monitor. This is done by attaching the platform to the seating apparatus, thereby maintaining a fixed relation between the user and the pointing device, as opposed to between the pointing device and the monitor.
One such device provides for the attachment of an arm and mouse support platform attached to one side of the seating apparatus. The means for attachment to the seating apparatus, unfortunately, limits its use in an office environment as it must only be attached onto the center column of a chair. Furthermore, the mouse support platform remains fixed relative to the arm support.
Another device which attempts to solve the problem of the repetitive motion of extending and reaching for a computer mouse provides for a plate that is attached onto the armrest of a chair. The plate extends forward of the armrest and is adjustable for wrist supination and pronation by allowing for tilting along an axis parallel to the user's line of sight to the monitor. There is no capability for adjustment of wrist angle, and the device must be affixed to the armrest using bolts, thus limiting its adaptability and portability.
Yet another device which attempts to solve the aforementioned problems associated with cumulative trauma injuries provides for a mouse support pedestal for a mouse platform, in conjunction with opposed clamping mechanisms for attachment onto the armrest of a chair. The platform is linearly adjustable along an axis parallel to the user's line of sight to the monitor, however, it fails to provide for adjustment to accommodate wrist supination or pronation nor wrist tilt angle. Although the armrest attachment mechanism appears to be adaptable to a variety of armrests, its massive opposing clamp approach renders the entire device unwieldy and cumbersome.
It can be seen that the aforementioned devices, as well as the myriad of related devices known in the art, fail to solve all the problems associated with cumulative trauma injuries resulting from use of computer pointing devices. Additionally, these devices have either been too limited to meet all the users needs or are too cumbersome to use or implement, and thus, do not provide enough flexibility for use in an office setting. Therefore, there is a need for a computer pointing device support apparatus that provides for placement of a pointing device, such as a mouse or the like, in a generally fixed position relatively to the user, while also providing for multi-axial adjustability of the support member, as well as universal adaptability to a variety of chairs armrests. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.